Author Topic: Pyrodex  (Read 34431 times)

Offline Daryl

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Re: Pyrodex
« Reply #75 on: June 10, 2016, 07:26:05 PM »
JOE is right.  I only mentioned the urine as I've read some WW1 soldiers used urine during the war when water was hard to come by.
Daryl

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Offline Mad Monk

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Re: Pyrodex
« Reply #76 on: June 17, 2016, 12:00:27 AM »
I have an extensive chemistry background, I am not speculating.  The ingredients of concern are salts.  They are easily dissolved in water.  Think about it, if you had a dried salty mess in the kitchen, would you use pee?, ammonia solution?, oil?, or water to clean it up?  Water right?  The fouling does not consist of acids that need to be neutralized.  Any weak acids, like sulfurous, will be flushed out by water.   Pee, ammonia solution and such only works because they're mostly water.   Urea and ammonia are not good to put on steel.  They will promote rust too.  People make this much more complicated than it needs to be. 

BTW, Yes, I have shot lots of corrosive high power ammo. I bought and shot, cases of 8mm and 303 corrosive ammo.   It is not a big deal.  No magic involved.  Thoroughly flushing the barrel with water and then cleaning as usual, it works perfectly.  I never had a speck of rust in any rifle from corrosive ammo.  Just plain old water, really. 

The problem comes when water is avoided as a cleaning agent. Some think that water is bad.   They get nervous abut putting water in their rifle.  They can 't say why but it give them the "willies".  Actually, water is free and is the most effective solvent.  There is nothing better.






Corrosive ammo vs Pyrodex.

The ammo you comment on was corrosive because the primers used a small amount of a chlorate or perchlorate.  In the case of Pyrodex you are looking at 17 parts of potassium perchlorate as part of the oxidizer system.
During powder combustion the potassium perchlorate simply liberates the oxygen leaving minute crystals of potassium chloride scattered over the barrels interior surfaces.  Under the right conditions these minute crystals will form electrolytic corrosion cell sites and cause pit corrosion in the surfaces of the bore.

The basic concept behind Pyrodex is the use of sodium benzoate as the "fuel".  The amount of charcoal in Pyrodex is so small as to be meaningless in actual powder combustion.  But the combustion reaction rates are so slow with the sodium benzoate that a good healthy slug of potassium perchlorate is needed to get burn rates up to where it will work as a propellant powder.  The formula also includes a few parts of dicyanamide as a pre-combustion corrosion prevention.  But during powder combustion the temperature is high enough to decompose it so there is no post-combustion corrosion prevention.

When Hodgdon developed the Triple Seven they replaced the sodium benzoate with sodium dinitrobenzoate sulfonate.  Highly reactive with charcoal.  So in 777 you find a lot more charcoal than is found in Pyrodex and with the rapid reaction rate with the dintro there is no need for the perchlorate.
The presence of sulfur and charcoal in Pyrodex was more of a window dressing thing to get it viewed as a modification of black powder.  Without the perchlorate in the 777 it will not cause pit corrosion in the gun.

Offline Scota4570

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Re: Pyrodex
« Reply #77 on: June 17, 2016, 08:36:11 PM »
Mad Monk

Thanks for setting us straight.  I always enjoy your posts  because they are base on facts. 

Scot

Offline Mad Monk

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Re: Pyrodex
« Reply #78 on: June 18, 2016, 02:39:23 AM »
Mad Monk

Thanks for setting us straight.  I always enjoy your posts  because they are base on facts. 

Scot

I should have added that 777 was developed out of the Pyrodex formula to help out the in-line shooters.  The in-line shooters wanted velocities higher than what Pyrodex can produce.

When the in-line crowd began to shoot with the plastic sabots Pyrodex created a nasty problem for them.  The thing about Pyroex leaving a lot of tiny crystals of potassium chloride scattered in the bore.  When you would try to run a saboted pistol bullet down the bore the crystals of potassium chloride, from a previous shot, would be forced into the soft plastic of the sabot.  You would get a saboted round about half way down the bore and it could not be seated on the charge.  The shooter would have to remove the breech and beat the saboted pistol bullet back out the muzzle.  So with the 777 formula not having potassium perchlorate one could readily run another sabot down the bore.  But the 777 is a "hot" powder.  If you get a bit happy with charge size it will leave patches of a glass like film in the bore down in the breech area.  That would also make loading a follow up charge and saboted bullet almost impossible.

In a choice between Pyrodex and 777 I would go with the 777 but watch my charge sizes relative to that glass like film formation above a certain charge size.

Offline bgf

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Re: Pyrodex
« Reply #79 on: June 18, 2016, 06:16:45 AM »
Mad monk,

Great posts.  I forgot about the glassy ring above the charge with 777, but that is something to look out for!  Had it happen to some degree with Swiss 3f also... 

I liked 777 in caplocks but it is a little hard to set off.  Duplex charges help, but are a troublesome in practice.  Is there any new stuff that tops 777 in traditional sidelocks or even flintlocks?  I know it is anathema to even consider substitutes, but I like to know what options are out there.  Even pyrodex shot pretty good, but the perchlorate makes me avoid it in everything but a pistol where I can really give the barrel a bath :).

Offline Dphariss

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Re: Pyrodex
« Reply #80 on: June 18, 2016, 08:33:11 AM »
I have an extensive chemistry background, I am not speculating.  The ingredients of concern are salts.  They are easily dissolved in water.  Think about it, if you had a dried salty mess in the kitchen, would you use pee?, ammonia solution?, oil?, or water to clean it up?  Water right?  The fouling does not consist of acids that need to be neutralized.  Any weak acids, like sulfurous, will be flushed out by water.   Pee, ammonia solution and such only works because they're mostly water.   Urea and ammonia are not good to put on steel.  They will promote rust too.  People make this much more complicated than it needs to be. 

BTW, Yes, I have shot lots of corrosive high power ammo. I bought and shot, cases of 8mm and 303 corrosive ammo.   It is not a big deal.  No magic involved.  Thoroughly flushing the barrel with water and then cleaning as usual, it works perfectly.  I never had a speck of rust in any rifle from corrosive ammo.  Just plain old water, really. 

The problem comes when water is avoided as a cleaning agent. Some think that water is bad.   They get nervous abut putting water in their rifle.  They can 't say why but it give them the "willies".  Actually, water is free and is the most effective solvent.  There is nothing better.



I used to work professionally in the field of BP firearms. Most people with a chlorate pitted bore don't know what they are looking at until its FAR too late. This is based on people coming by the factory, being told that Pyrodex was not recommended, telling me that they used it for years with no pits. If they had the firearm with them I would shot them the pitting and they would clam up. One guy with "no pitting" had pitted a Ruger OA to the point he had it reblued (the fouling is a great blue remover too) pits and all....
Dan
He who dares not offend cannot be honest. Thomas Paine

Offline Mad Monk

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Re: Pyrodex
« Reply #81 on: June 18, 2016, 07:52:26 PM »
Mad monk,

Great posts.  I forgot about the glassy ring above the charge with 777, but that is something to look out for!  Had it happen to some degree with Swiss 3f also... 

I liked 777 in caplocks but it is a little hard to set off.  Duplex charges help, but are a troublesome in practice.  Is there any new stuff that tops 777 in traditional sidelocks or even flintlocks?  I know it is anathema to even consider substitutes, but I like to know what options are out there.  Even pyrodex shot pretty good, but the perchlorate makes me avoid it in everything but a pistol where I can really give the barrel a bath :).


When Hodgdon first introduced 777 they stated it was only for in-lines using shotshell primers.  The ignition temperature of 777 is a little above that of Pyrodex.  I shot it in my Lyman Trade Rifle with the classic breech.  Unreliable ignition.  I tried various strength caps.  Tried an adapter that used the 209 shotshell primers.  That worked.  most of the time.  After 3 or 4 firings I would have to take the adapter apart and clean it.

Then I shot it in my Lyman Great Plains Rifle that had originally been a flintlock later converted over to a mule ear lock with one of Bernie Tolino's early mule ear locks.  Using magnum caps it would go off every time since the nipple was firing directly into the rear of the charge.  With the 777 in the mule ear lock gun it was a pleasure to shoot.